Lock-stitch sewing-machine



M. HEMLEB.

LOCK STITCH SEWING MACHINE.

APPLICATION FILED MAR.2I, I917.

1,378,677. Patented May 17,1921.

4 $HEETSSHEET 1.

WITNESS INVENTOR firm/M IVI. HEMLEB.

LOCK STITCH SEWING MACHINE.

APPLICATION FILED MAR.2I,1917.

1,378,677. A V P ted May 17,1921.

4 SHEETS SHEET 2.

WITN E53 M. HEMLEB.

LOCK STITCH SEWING MACHINE- APPLICATION FILED 111111.21, 1911.

Patented May 17,1921.

4 SHEETSSHEET 3.

E W m ATTORNEY M. HEMLEB.

' LOCK STITCH SEWING MACHINE.

APPLICATION FILED MAR. 21, 1917- 1,378,677. Patented May 17,1921.

4 SHEETS-SHEET 4.

7Ma-/M WITNESS.

UNITED STATES PATENT OFFICE.

MARTIN HEMLEB, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO THE SINGER MANU- FACTURING COMPANY, A CORPORATION OF NEW JERSEY.

LOCK-STITCH SEWING-MACHINE.

Specification of Letters Patent.

Patented May 17, 1921.

Application filed March 21, 1917. Serial No. 156,357.

To all whom it may concern:

Be it known that I, MARTIN HE LEB, a citizen of the United States, residing at Elizabeth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Lock-Stitch Sewing-Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

The present improvement relates to lockstitch sewing machines of the so called commercial spool type wherein an ordinary spool of thread is used, in lieu of the usual bobbin, for the purpose of affording a relatively large supply of under thread and effecting a saving of time and trouble attendant upon frequent rewinding of the bobbin.

The various commercial spool machines now known, however, are of a complicated nature and are costly to manufacture. The constructions are such that the removal and replacement of the relatively large lower thread-mass 'is difficult of accomplishment. Many of said machines are noisy in operation because of the presence of cams formed with harsh or sharp curves to secure the necessary motions. Others of said machines are hard-running and uncertain in their operation particularly at the speed now demanded of a practical machine.

One object of the present invention is to provide a lock-stitch machine of simple construction which will operate quietly and effectively at high speed and which will accommodate a relatively large lower threadmass preferably in the form of a commercial spool of thread of any size and shape within certain maximum limits.

A further object of the invention is to provide a lock-stitch machine adapted to accommodate a relatively large lower spool of thread and so constructed that the removal and replacement of said spool may be accomplished with a minimum expenditure of time and effort on the part of the operator.

A further object of the invention is to provide a commercial spool machine with a link take-up and slack-thread controlling device adapted to properly handle a length of needle'thread consequent upon the formation of a relatively large needle-loop which must be drawn out to encompass the lower thread mass.

The above and other objects, to be more fully referred to hereinafter, are attained by the present improvement which, in its preferred embodiment, comprises a fiat-bed machine-frame including the usual overhanging arm for the needle-actuating mechanism. To cooperate with the needle a circularly moving hook or loop-taker is provided. Inthe present instance the looptaker comprises a skeletonized cup-shaped member whose circular rim is formed with an inwardly directed loop-seizing beak and a peripheral groove within which is journaled a stationary thread-case-supporting plate having a centrally disposed rectangular aperture within which is seated a large cylindrical thread-case. The thread-case is formed preferably with diametrically opposed projections affording shoulders which rest upon said plate and support the threadcase within the field of action of the looptaker beak.

The thread-case-supporting plate carries downwardly extending curved fingers which act to deflect the lower limb of the needleloop downwardly while the threadcase itself is formed with an inclined wall-portion affording an inclined surface which acts to deflect the upper limb of the needle-loop upwardly. The curved fingers and inclined surface referred to act to spread the needle loop so that it may be passed about the thread-case. A pair of spaced apertures of large size formed in the upper side of the thread-case define a lengthwise extending bar which is adapted to be seized as a fingerpiece in lifting the thread-case from its seat in the supporting plate.

The circularly moving loop-taker is preferably fixed to the upper end of a shaft which extends upwardly and outwardly away from the needle-path and, in the present embodiment of the invention, is geared to the main-shaft to rotate at double the speed of the latter. The axis of the cylindrical thread-case is substantially coincineedle-loop near the throat-plate, whereby the use of a comparatively short needle is permitted, while the thread-case, which projects considerably above the plane of actlon of the loop-taker, is spaced slightly below the level of the throat-plate and may be lifted from and replaced in operative position in a very simple and direct manner. A rotation-restraining device is provided to cooperate with the thread-case supporting plate to hold the latter stationary during the operation of the loop-taker.

A link take-up of special construction is provided to quickly take up the relatively large loop drawn out by the loop-taker and to properly control the slack-thread during the down-stroke of thetake-up while the loop-taker is performing the last part of idle rotation and the first part of its loopcasting rotation. .In the present instance, the take-up comprises a bifurcated arm provided with a pair of spaced and alined thread-eyes which are moved in a closed path of irregular outline. The take-up actuating linkage is such that the thread-eyes are given a quick up-stroke to completely draw up the needle-loop before the looptaker beak reaches theend of its loop-casting rotation. A slack-thread controller,

having preferably the form of a thread-camfashioned from wire, is disposed between the bifurcations of the take-up arm and acts to absorb the slaclrthread given up by the take-up during the first part of its relatively slow down-stroke.

A fuller understanding of the invention may be had by referring to the accompanying drawings, in which Figure 1 is a side ele-. vation of the machine with a portion of the bed-plate broken away to show the looptaker. Fig. 2 is a front elevation of the machine with the face-plate for the take-up removed. Fig. 3 is a plan view of the front end-portion of the bed-plate showing the loop-taker disposed directly below the usual slide-plate opening. Fig. 4 is a perspective view of the threadcase. Fig. 5 is a plan view of the loop-taker and lower threadsupplying mechanism. Fig. 5 is a fragmentary perspective view of the loop-taker.

Fig. 6 is a bottom plan view of the station-- ary thread-case-supporting plate. Fig. 7 isa vertical section through the longitudinal axis of the thread-case. Fig. 8 is a section through the loop-taker and thread-case in a plane at ri ht angles to the axis of the thread-case and coincident with the axis of the loop-taker. Fig. 9 is a vertical section along the line a-a, Fig. 5. Fig. 10 is a plan view of the take-up and its actuating mechanism. Figs. 11, 12 and 13 are front end-elevations showing the take-up and loop-taker in different successive stages of a stitch-forming cycle.

In the particular embodiment of the invention illustrated, the machine frame is of the usual flat-bed type and comprises a bedplate 1 from one end of which rises a standard? carrying the tubular bracket-arm 3 side of which is closed by the usual faceplate 4. Journaled within the bracket-arm 3 is the main-shaft 5 whose forward end carries a crank-arm 6 to which is secured a take-up actuating crank pin 7 which supports a second crank-arm 8 carrying a needle-bar actuating crank-pin 9 angularly. spaced from and in advance of the crankpin 7. The crank-pin 9 is connected by the link 10 to the reciprocating needle-bar 11 carrying the eye-pointed needle 12. Journaled below the bed-plate 1 is a loop-taker actuating shaft 13 which is driven by the main-shaft 5 through suitable gear connections with the vertical shaft 14 journaled within the standard. At its forward end the shaft 13 carries a bevel gear 15 which meshes with a companion gear 15' of .onehalf its size carried by, the upwardly extending look-taker or rotary hook supporting shaft 16 which is journaled in the bushing 17 fixed within a bearing aperture in the outwardly and forwardly curved bearing lug 18. The shaft 16 is inclined upwardly and outwardly away from the needle-path and standard 2, as shown in F i 1.

Fixed to the upper end of the shaft 16 is the preferably skeletonized and cup-shaped loop-taker body-portion 19 whose rim 20, Figs. 7 and 8, is grooved at 21 to receive and support the periphery of the circular bobbin-case supporting plate 22. Secured to the rim 20 is the open ring-shaped member 23, one end of which is formed with the inwardly directed loop-seizing beak or hook 24. The other end of the ring-shaped member 23 is formed with a loop-detaining shoulder 25 and tail-piece 26 which is connected by means of a thin sheet-metal bridge 27 with the hook-supporting end of the open ring 23 and forms, together with the beak 24, a throat 28" into which the needleloops are directed for passage about the threadcase. The loop-taker ring 23 serves to confine the plate 22 within the bearing groove 21. r

The thread-case-supporting plate .,22 is formed with a large rectangular aperture 29' to receive the cylindrical thread-case 30 and is peripherally cut away at 31 to form the stationary hook 32 which catches the lower limb of the needle-loop fondeten'tion in the opening 31 until said loop has been passed about the thread'case and the thread-detaining shoulder 25 has reached a point adjacent said opening 31 to permit escape of the needle-loop. Secured to the under surface of the plate 22 by screws 33 is a deflector 34 for the lower limb of the needle-loop. In the present instance, the deflector 34 is formed with two downwardly extending, curved, deflector fingers 35,35 which assist in opening the needle-loop as it isbeing "terminating in the hollow head 4, the front drawn out by the hook or loop-taker for passage about the thread-case 30. The circular plate 22 is provided at its edge with the usual notches 35 to keep the groove 21 clear of thread or lint.

Secured to the upper surface of the plate 22 by means of a screw 35 and steady-pin 36 is a finger 37 which is loosely embraced by the notched pOItiOIl 38 of a rotation restraining bar 39 secured to the under surface of the bed 1 and bridging the opening 39' in said bed normally closed by the usual throat-plate 41 and slide-plate 42. A curved leaf-spring 43 is secured at one end to the plate 22 adjacent the finger 37. The free end of said spring 43 is spaced from the free end of the finger 37 and bears lightly and resiliently against one side wall 'of the notch 38 when the machine is in operation. This construction permits the ready escape of the needle-loops over the free ends of said finger and spring but prevents undue rattling of the finger 37 in the notch 38 when the machine is operated at high speed.

The thread-case 30 is made up in the form of a skeletonized open-ended cylinder and is proy'ided with diametrically opposed lateral projections 40, 40 Figs. 4 and 5, which are adapted to rest upon the upper surface of the thread-case supporting plate 22 and sustain the thread-case within the aperture 29 with its open end uppermost and with its axis, in the embodiment herein shown, substantially coincident with the plane of action of the loop-taker beak 24 and inclined upwardly toward the needle-path. The lower or closed end of the thread-case supports a light spring-catch 41 which cooperates with the plate 22 to prevent accidental upward displacement of the lower end of the thread-case relatively to the plate 22. The springcatch 41 is so shaped that it will yield to an upward pull on the threadcase. Accidental upward displacement of the upper end of the thread-case is prevented by the slide-plate 42 which is spaced slightly above said upper end, as shown in Fig. 1. V

The upper side-wall portion of the cylindrical thread-case is extended outwardly and downwardly at 43, Figs. 2 and 8, into contact relation with the plate 22 near the looptaker ring 23. The inclined portion 43 of the thread-case serves as a deflector for the upper limb of the needle-loop, as shown in Fig. 5.. In order that the thread-case may be readily seized for removal from operative position, it is provided preferably with spaced finger-clearance apertures 44, 45, Fig. 4, which define a finger-piece 46, extending lengthwise of the thread-case.

The lower thread-tension device comprises a fiat-spring 47having spaced tail-pieces 48 whose free ends enter corresponding apertures 49 in the thread-case wall. The spring 47 is secured to the finger-piece 46 by a single tension-adjusting screw 50 and, at its upper end, is formed with a pair of spaced down turned projections 51, Fig. 9, each of which enters a corresponding aperture in the thread-case. On of the projections 51 is beveled at 52 to permit easy insertion of prises a take-up arm 55 one end of which is bifurcated, as shown in Fig. 10. The free ends of the bifurcations 56 of the arm 55 are apertured at 57 to receive the needlethread. The other end of the arm 55 is joined to a cross-bar or link 55 one end of which is apertured to embrace the take-up crank-pin 7 whose shank is secured in a socket in the crank-arm 6 by the set-screw 7 Fig. 10. The opposite end of the link 55' is pivotally connectedwith one end of an anchor link 58 whose opposite end is pivoted to the frame at 59.

To absorb the slack-thread during the first part of the down-stroke of the take-up while the hook is executing the last part of its idle rotation and the first part of its loop-casting rotation the slack-thread controlling device 60 is provided. In the present instance this device comprises a thread cam element fashioned from wire and secured to the head 4 by screws 61 and 62 in such a position that it will engage the thread between the bifurcations ofthe take-up arm.

The present machine is equipped with feeding mechanism of the usual four-motion type and as the specific construction thereof forms no part of the present invention it is deemed unnecessary to further describe the same.

When it is desired to thread up themachine the slide-plate 42 is shifted to uncover the thread-case 30 whereupon the latter may be readily picked or lifted from its seat upon the stationary plate 22. An ordinary spool of thread of any of the usual sizes is slipped into the open end of the thread-case and the free end of the thread is drawn into the drawn out and cast over the thread-case, as shown in igs. 5 and 2. At the point of the cycle shown in Fig. 2, the take-up is beginning its quick up-stroke along the path indicated by the dot-and-dash line. In the position shown in Fig. 11, the take-up has almost reached the limit of its upward movement and the needle-loop has been completely drawn up to the work, while the hook 24 has not yet completed its first or active rotation. The so-called second looping or i I catching of thread by the hook on its idle rotation is thus avoided; The thread required by the take-up to complete its upstroke is supplied by the yielding action of the usual check spring 0 carried by the tension device 0'.

Between the positions shown in Figs. 11 and 12 the hook is performing its idle rotation and the take-up is executing the first part of its down-stroke and is giving up thread faster than the thread-is being absorbed by the descending needle. In Fig. 12

the needle has reached the limit of its downstroke and there is nothing below the bedplate to draw on the needle-thread until the On account of the inclined position of'thethread-case, a spool of thread loosely housed therein will gravitate to and remain in contact with the lower end wall of said threadcase and there will be no tendency for the spool to rattle within the thread-case during the operation of the machine.

While I have shown and described the preferred embodiment of the invention, it is to be understood that the essential elements thereof are susceptible of material modification without departure from the spirit of the invention. Various modifications of the structure shown and described may obviously be made within the scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, in combination, a reciprocating needle, a circularly moving loop-taker, a take-up, a thread-case sup ort sustained by said loop-taker, and a threadcase sustained by. said support, said threadcase bein formed with an elongated threadmass cavity whose longest dimension is insustained by said loop-taker, and a threadcase sustained by said support, said threadcase being formed with a cylindrical threadmass cavity whose axis is inclined upwardly toward-the needle-path and transverselyof the line of seam-formation. I

3. -In a sewing machine, in combination, a reciprocating needle, a circularly moving loop-taker operating on an axis inclined at an acute angle to the axis of the needle, and a thread-case sustained within the field of action of said loop-taker and having a cylindrical thread-mass cavity the axis of which extends transversely of the axis of rotation of the loop-taker.

4. In a sewing machine, in combination, a reciprocating needle, a circularly moving loop-taker, operating in a plane inclined to the needle-path, a take-up, a thread-case support sustained by said loop-taker, and a thread-case sustained by said support, said threadcase being formed with a cylindrical thread-mass cavity, whose axis is disposed substantially at right angles to the axis of movement of said loop-taker and is inclined upward-1y toward the needle-path. v

5. In a sewing machine, in combination, a reciprocating needle, 'a take-up, a circu larly moving loop-taker formed with a beak operating in a plane inclinedto the needlepath, and a thread-case sustained by said loop-taker and formed with a cylindrical 106 thread-mass cavity whose axis is substantially coincident with the plane of action of said beak. t 1

6'.- In a sewing machine, in combination,.a flat work-support including a shiftable 110 cover-plate, a reciprocating needle mounted above said work-support, a take-up, a cir- 'cularly moving loop-taker formed with a beak and mounted below said cover-plate; an apertured thread-case support journaled in said loop-taker, a rotation-restraining device cooperating with said thread-case support, a thread-case removably situated within the aperture in said support and 'formed[ with a cylindrical thread-mass cavity whose axis is substantially coincident with the plane of action of said beak and is inclined upwardly toward the needle-path, said coverplate serving when in closed position to prevent upward displacement of said threadcase, but permitting the ready removal of said thread-case when in open position.

7. In a sewing machine, in combination, a reciprocating needle, a take-up, a circularly moving loop-taker, a thread-case support 18) with an upwardly opening thread-case-receiving aperture, a thread-case formed with a cyl ndrical thread-mass cavity arranged with its axis transversely of the axis of rotation of the loop-taker and removably situated within said aperture, and means sustamed by said thread-case support for defleeting the lower limb of the needle-loop under the thread-case, said thread-case be- 1ng shaped to deflect the upper limb of the needle-loop thereover.

9. In a sewing machine, in combination, a thread-case support formed with an upwardly opening thread-case-receiving aperture, and a thread-case removably sustained Within said aperture and formed with finger clearance apertures defining a finger-piece by means of which it may be readily lifted from operative position.

10. In a sewing machine, in combination,

a reciprocating needle, a circularly moving loop-taker operating in a plane inclined to the needle-path, an apertured thread-case supporting plate sustained within the field of action of the loop-taker, and a cylindrical thread-case removably seated upon and within the aperture of said plate. t 11. In a sewing machine, in combination, a reciprocating needle, a'circularly moving loop-taker mounted on a shaft inclined to the needle-path, a stationary thread-case support sustained within the field of action of'said loop-taker and a readily removable thread-case sustained by said support.

12. In a sewing machine, in combination, a frame comprising a flat cloth-plate, a reciprocating needle sustained above the cloth-plate, a take-up, a circularly moving loop-taker sustained below the cloth-plate for operation in a plane parallel with the line of seam-formation and inclined downwardly from the cloth-plate, and a relatlvely large thread-case sustained by sald looptaker and including a portion which projects above the plane of action thereof.

13. In a sewing machine, in combinatlon, a reciprocating needle, a circularly moving loop-taker operating in a plane inclined to the needle path, a stationary thread-case support sustained within the field of action of said loop-taker, loop-deflecting means carried by said thread-case support and disposed mainly below the plane of action of said loop-taker, and a thread-case removably supported by said thread-case support and formed with an inclined loop-deflecting surface disposed mainly above the plane of action of said loop-taker.

14:. In a sewing machine, in combination, a reciprocating needle, a loop-taker, an apertured thread-case supporting plate ar-' ranged in a plane inclined to the needlepath, a cylindrical thread-case formed with an end wall and sustained within the aperture of said support, and a spring-catch mounted upon the end-wall of said threadcase and adaptedto cooperate with the under surface of said thread-case supporting plate to prevent accidental upward displacement of said thread-case from operative position. x

15. In a sewing machine, in combination, a thread-case support formed with an upwardly opening thread-case-receiving aperture, a thread-case removably sustained within said aperture and formed with finger-clearance apertures defining a fingerpiece by means of which it may be readily lifted from operative position.

16. In a sewing machine, in combination,

a thread-case support formed with an upwardly opening thread-case-receiving aperture, a thread-case removably sustained within said aperture and formed with finger-clearance apertures defining a fingerpiece by means of which it may be readily lifted from operative position, and a tension device mounted upon said finger-piece.

17. In a sewing machine, in combination, a thread-case support formed with an upwardly opening thread-case-receiving aperture, a thread-case removably sustained within said aperture and formed with finger-clearance apertures defining a fingerpiece'by means of which it may be readily lifted from operative position, and a threadtension spring superimposed upon and extending lengthwlse of said finger-piece in reciprocating needle, a rotary loop-taker and actuating means for said needle and looptaker adapted to cause the loop-taker to make a plurality of rotations for each reciprocation of the needle, of a link take-up, and means cooperating with said take-up to control the excess slack-thread given up during the down-stroke of the take-up while the loop-taker is executing the last part of an idle rotation and is seizing a needle-loop.

20. In a, sewing machine, the combination with stitch-forming mechanism including a reciprocating needle, a rotary loop-taker and actuating means for said needle and looptaker adapted to cause the loop-taker to make a plurality of rotations for each reciprocation of the needle, of a link take-up, and a thread-engaging cam having a convex portion adapted to cooperate with said takeup to control the excess slack-thread given up during the down-stroke of the take-up while the loop-taker is executing the last part of an idle rotation and is seizing a' needle-loop.

21. In a sewing machine, the combination with stitch-forming mechanism including a reciprocating needle, a rotary loop-taker, and actuating means for said needle and loop-taker adapted to cause the loop-taker to make a plurality of rotations for each reciprocation of the needle, of a link take- I up comprising a bifurcated take-up arm, and

a stationary thread-cam having a curved portion adapted to act upon the thread inter-- mediate the bifurcations of said take-up arm to absorb slack-threadgiven up by said takeup arm while the loop-taker is completing an idle rotation and seizing a needle-loop.

22. In a sewing machine, in combination, a reciprocating needle, a rotary loop-taker adapted to make a plurality of revolutions to one reciprocation of the needle, a link take-up device formed With'spaced threadgniding eyes operating in parallel planes,

and a thread-engaging device disposed between the planes of action of said eyes and adapted to absorb slack-thread produced by the thread-giving action of said eyes during the last part of an idle rotation and the first part of a loop-casting rotation of said looptaker.

23. In a sewing machine, in combination, a

reciprocating needle, a rotary loop-taker adapted to make a plurality of revolutions to one reciprocation 0f theneedle, a link take-up device formed With spaced threadguiding eyes operating in parallel planes,

and a stationary thread-cam disposed between the planes of action of said eyes and adapted to absorb slack-thread produced by the thread-giving action of said eyes during the last part of an idle rotation and the first part of'a loop-casting rotation of said looptaker.

MARTIN HEMLEB. 

